PCI/MSI: Fix msi_capability_init() kernel-doc warnings

Fix kernel-doc warnings in pci/msi.c:

  ..//drivers/pci/msi.c:623: warning: No description found for parameter 'affd'
  ..//drivers/pci/msi.c:623: warning: Excess function parameter 'affinity' description in 'msi_capability_init'
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>

drivers/pci/msi.c

@@ -610,7 +610,7 @@ static int msi_verify_entries(struct pci_dev *dev)
  * msi_capability_init - configure device's MSI capability structure
  * @dev: pointer to the pci_dev data structure of MSI device function
  * @nvec: number of interrupts to allocate
- * @affinity: flag to indicate cpu irq affinity mask should be set
+ * @affd: description of automatic irq affinity assignments (may be %NULL)
  *
  * Setup the MSI capability structure of the device with the requested
  * number of interrupts.  A return value of zero indicates the successful